1. Field of the Invention
The present invention relates to color photographic light-sensitive materials, more particularly, the invention pertains to color photographic light-sensitive materials having high saturation and which are excellent in color reproduction.
2. Description of the Prior Art
The use of the interlayer inhibiting effect has been known as a useful means for improving color reproduction of color photographic light-sensitive materials. In color negative light-sensitive materials, for instance, the development inhibiting effect from a green-sensitive layer to a red-sensitive layer may inhibit color production in the red-sensitive layer upon white light exposure to a greater extent than upon red light exposure. In a color negative film-color paper system, gradation is balanced so that an exposed area upon white light exposure reproduces gray color on a color print, and therefore the interlayer effect leads to greater cyan dye-formation upon red light exposure than upon gray light exposure. As a result, there may be reproduced from the color negative film a color print with decreased cyan dye-formation, that is, with reproduction of highly saturated red color. Similarly, a development inhibiting effect from a red-sensitive layer to a green-sensitive layer leads to reproduction of green colors having higher saturation.
One of the methods for increasing the interlayer effect so far known is a method using iodide ion released upon development from a silver halide emulsion. In this method, the silver iodide content of the donor layer of the interlayer effect is high, while the silver iodide content of the receptor layer is low. Another method for increasing the interlayer effect is, as described in Japanese Patent Application (OPI) (unexamined published application) No. 50-2537, one in which the donor layer of the interlayer effect includes a coupler which reacts with the oxidation products as of a paraphenylene diamine type color developer to release a development inhibiting compound. Still another method for increasing the interlayer effect is one called an auto-masking method in which a colored coupler is incorporated in an uncolored coupler-containing layer to mask unwanted absorption of the colored dye produced upon development from the uncolored coupler. According to this method, it is possible to obtain an effect similar to the interlayer effect by increasing the amount of the colored coupler incorporated so that masking is effected to a greater extent than that necessary to mask the unwanted absorption of the colored dye produced from the uncolored coupler.
The increase in the saturation of primary colors, i.e., red, green and blue according to any one of these methods leads to a problem such that the hue of yellowish or cyanic green cannot be reproduced faithfully. To solve this problem, a method has been proposed, which is, for instance, disclosed in Japanese Patent Appln. (OPI) No. 61-34541 (USSN 751,961, EP 85108369.1). This technique intends to accomplish a color image with a faithful color reproduction and having a good sharpness by providing a silver halide color light-sensitive material comprising on a support at least one blue-sensitive silver halide emulsion layer containing a yellow dye-forming color coupler, at least one green-sensitive silver halide emulsion layer containing a magenta dye-forming color coupler and at least one red-sensitive silver halide emulsion layer containing a cyan dye-forming color coupler, in which the weight-averaged wavelength (.lambda..sub.G) of spectral sensitivity distribution of said green-sensitive silver halide emulsion layer is in the range of between 520 nm and 580 nm, the weight-averaged wavelength (.lambda..sub.-R) of the wavelength distribution of the interlayer effect received by said red-sensitive silver halide emulsion layer in the range of between 500 nm and 600 nm is in the range of between 500 nm and 560 nm and the difference (.lambda..sub.G -.lambda..sub.-R) is 5 nm or more.
In this respect, the weight-averaged wavelength (.lambda..sub.-R) of the wavelength distribution of the interlayer effect received by the red-sensitive silver halide emulsion layer in the range of between 500 nm and 600 nm can be obtained as follows:
(1) The cyan dye-forming red-sensitive layer which is sensitive to radiation having a wavelength longer than 600 nm is uniformly exposed through a red filter (which transmits only radiation to which the red-sensitive layer is sensitive and to which the other layers are insensitive) or an interference filter (which transmits only radiation having a specific wavelength) to uniformly fog the cyan dye-forming red-sensitive layer to an appropriate optical density.
(2) The spectrum exposure is made to cause the interlayer development inhibiting effect on the fogged emulsion layer from the blue-sensitive and the green-sensitive layers. As a result, a reversal image is obtained (see FIG. 1A).
(3) From this reversal image, the spectral sensitivity distribution S.sub.-R (.lambda.) as a reversal light-sensitive material is found. The relative value of S.sub.-R (.lambda.) at a specific wavelength (.lambda.) can be found at the point (a) in FIG. 1A.
(4) The weight-averaged wavelength (.lambda..sub.-R) of the interlayer effect is calculated according to the following equation: ##EQU1##
While the weight-averaged wavelength (.lambda..sub.G) is defined by the following equation. ##EQU2## wherein S.sub.G (.lambda.) is a spectral sensitivity distribution curve for a green-sensitive layer and the relative value of S.sub.G (.lambda.) at a specific wavelength (.lambda.) can be found at the point (b) in FIG. 1B.
According to procedures similar to those discussed above, spectral sensitivity distributions S.sub.-B (.lambda.) and S.sub.-G (.lambda.) can be obtained by selecting a suitable interference filter, fogging the blue-sensitive and the green-sensitive layers and then exposing a light of equienergy spectrum to the fogged layers.
However, it is quite difficult to always reproduce faithfully, colors of the spectral light over the whole range of wavelength of visible light with utilizing such a light-sensitive material. U.S. Pat. No. 3,672,898 discloses a method which comprises limiting the spectral sensitivity distributions of the blue-sensitive, the green-sensitive and the red-sensitive silver halide emulsion layers to a certain range to provide a photographic light-sensitive material which makes it possible to faithfully reproduce colors and restrict the occurence of drastic change in the color reproduction even if it is exposed to a variety of light sources.
The inventors of this invention have conducted studies on various kinds of combinations of these methods described above except for Japanese Patent Appln. (OPI) No. 61-34541 to develop a photographic light-sensitive material capable of faithful color reproduction over a wide spectral range of visible light. However, a light-sensitive material which sufficiently meets the requirements for both saturation and faithfulness of hue has never been obtained. Possible reasons for this are as follows:
(i) If the spectral sensitivity is restricted to the range disclosed in U.S. Pat. No. 3,672,898, the color saturation of the resulting light-sensitive material is highly reduced;
(ii) If DIR compounds disclosed in Japanese Patent Application (OPI) No. 50-2537 are used to compensate the reduction in saturation or a strong masking with a colored coupler is effected to increase the color saturation, there is observed an inhibitory effect at the portion on which the spectral sensitivity distribution of blue-sensitive, green-sensitive and red-sensitive silver halide emulsion layers are overlapped with each other. As a result, a distortion of the spectral sensitivity distribution occurs, which leads to the deviation in hue.